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Automotive/1985 Ford Bus (E350 Chasis, 6.9L Diesel) Headight Question

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Expert: - 8/12/2007


Question
I bought a surplus Shuttle Bus from the USAF (no manual). It has sat for 3+ years and I am trying to get it on the road (registered). When I pull the light switch the headlights come on (two clicks). I am not sure if they are the high beams or the low beams (brand new lights). When I rotate the dimmer switch, either direction, nothing changes on the headlights (all the cabin lights were removed by the USAF).

My questions are: 1) Is there another way to turn on the high beams (I have tried all the switches I can find) assuming the low beams are on. 2) How can I test the dimmer switch (I have removed it) to see if that is the problem. 3) How do I test the relay switch, if it is not the other two.

Thanks in advance for your help.

Answer
From your description of the headlight switch, I get the impression that this switch is of the same old classical style used on my 78 E250, and on most other vehicles of the 70s, 60s, etc that predate the multi-function stalk switch of the past two decades.

If that is the case, then perhaps you should look to the left floor, under the parking brake pedal, for a dimmer switch.  This will be an alternate-action foot-operated pushbutton, and it will toggle the headlights between low beam and high beam.

Twisting the headlight switch serves to rotate a dimmer - current-limiting rheostat, in fact - but this serves only to modulate the intensity of the instrument panel lighting.

By the way, I would highly recommend installing headlight relays for each of low- and high-beam, so as to reduce the load on the headlight switch used in Fords of that vintage.  As the switch ages, the contacts will run hotter and, over time, the heat will be enough that the circuit breaker integral within the headlight switch will begin to cycle.  Further, wire the line side of the relays (contactors, actually) through correctly-sized (10A usually) Cole-Hersey or Bussmann auto-reset circuit breakers directly back to the battery terminal - this will result in brighter lights, and longer life for halogen lights.  The latter last best when the quartz envelopes are hot enough that filament material does not condense on the envelope and will redeposit on the filament when the lamp is turned off and cools down.

A shop manual for most Ford Vans of the era should give you most of the information you might need.  Get the electrical and vacuum systems manual, if you can get it.

Good luck with this project ... EGK

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Ernest (Ernie) Kenward

Expertise

The challenges I most enjoy are thoughtful technical questions of a trouble-shooting nature in both electrical, power electronic and mechanical systems, mainly automotive but also machine control and small-machine PLC applications. Please note, however, that I am NOT a walking shop manual! I DO, however, make it a point to have those manuals and other service literature for those vehicles I DO own, and highly recommend that anyone serious about maintenance or modification of their vehicles do the same; MOST of your answers WILL be found there. For that matter, I do NOT go out of my way to acquire shop manuals for any vehicle I do NOT own! That being the case, any general query to me along the lines of "What is the meaning of this code read from the ECU of my 2015 XYZ?" or "Where is the fuse for the windshield washer pump found?" (try your car's electrical distribution panel for a start!) will not go far. What I do offer is a pretty good collection of literature, insights and hands-on experience with 1950s to 1980's Ford products (plus a developing database of information and practice with the Mercedes diesel cars), along with an engineering perspective and the ability to design and implement custom control, electrical and mechanical subsystems for vehicles. For that reason, I am happy to make my thoughts and efforts available to those who are of like mind and/or are seriously making a point of learning about their vehicles. Use the Opportunity to Learn!

Experience

A key skill in my work and hobby pursuits both is STRATEGIC TROUBLESHOOTING. I am a senior instructor in Electrical Engineering Technology at a leading Canadian polytechnic, my areas being Electrical Power and Industrial Control, electrical and electronics design and manufacturing, and AutoCAD and related CAD/CAE software - plus equipment problem-solving and new equipment design and prototyping. Hobby-wise, I have 30-plus years of experience in auto restoration, mostly in electrical and mechanical systems. Ongoing projects include a 1959 Edsel Corsair, my 1978 Ford E250 class-B motorhome conversion, and the care and upkeep of my Mercedes 300CD. My vehicles become engineering test beds for electrical and mechanical upgrades as ideas present themselves. This includes the design and production of circuit boards to restore or enhance features for which no OEM replacement parts are obtainable, or where better specifications or reliability can be had via newer concepts. Regarding the E250 RV conversion, I designed and continue to revise a custom power distribution system, managed by a Programmable Controller (PLC); this has made most revisions as easy as uploading new firmware as I develop it. The "mini" PLC is a powerful device for custom automotive control systems. One good example (there are many) would be the Moeller "Easy Relay"; these offer a wealth of control, monitoring and variable-and-status display options for such projects. A good example project which has worked well is that one for my RV noted above, which has been on the job - revised in firmware only - for a decade now. It is a load management and charging control system to avoid the sulfation-induced early failure that often befalls deep-cycle batteries used in RV power applications. The battery installed in 2003 lasted long enough to more tnan pay for the PLC that contributed to its longer life ... and the PLC will be there for the next battery as well!

Organizations
IEEE - senior member ... past WCC Student Activities; SME - senior member ... past chair, greater Vancouver chapter chair 318; Edsel Owners' Club - have served in various capacities on chapter executive during seventies; have been Power and Driveline resource on the Edsel Owners' Club "E-team" for more than a decade.

Education/Credentials
Graduate of UBC

Awards and Honors
Certificates of appreciation from IEEE and SME for work in student and chapter activities

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